Video data having a large volume undergoes high-efficiency encoding before being transmitted from a transmitting device to a receiving device or being stored in a storage device. The term “high-efficiency encoding” refers to an encoding process for transforming a certain data string into another data string, for example, a process for compressing the amount of data. A high-efficiency video data encoding method includes an intra-picture (or intra) prediction encoding method and an inter-picture (or inter) prediction encoding method. In the intra prediction encoding method, video data having a high correlation in the spatial direction is utilized. For example, an image is encoded and decoded using only information concerning an image to be encoded. In the inter prediction encoding method, video data having a high correlation in the temporal direction is utilized. Video data is encoded by reference to a temporally close image with high similarity, for example, an image that has been encoded.
A related technique is disclosed in Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 13818, Generic coding of moving pictures and associated audio information, ISO/IEC 14496-10, MPEG-4 Part 10 Advanced Video Coding, or High Efficiency Video Coding (HEVC), which is a video coding scheme currently under joint development by the ISO/IEC and the International Telecommunication Union Telecommunication Standardization Sector (ITU-T).